RENEE MONTAGNE, HOST:
Today in Your Health, we're going to look at two screening tests for cancer and the costs of those tests. We begin with lung cancer, which is the No. 1 cancer killer in the world. Smokers are at the highest risk. Last February, Medicare began paying for some long-term smokers to be screened for the disease. Yet as lots of people get tested, there's a worry a lot more screening will do more harm than good. NPR's Anders Kelto reports.
ANDERS KELTO, BYLINE: It's really hard to detect lung cancer. Dr. Claudia Henschke, a professor of radiology at the Icahn School of Medicine in New York's Mount Sinai Hospital, says for years, the only tools doctors had were chest x-rays and the phlegm patients cough up.
CLAUDIA HENSCHKE: But unfortunately, they did not find the disease early enough.
KELTO: Regular x-rays can only see cancers when they're about the size of a quarter, and by then, it's often too late. But eventually, doctors began using something called a spiral CT scan to look for lung cancer. And Henschke says these high-resolution scans are much better.
HENSCHKE: You can see a nodule on a CT scan that's 2 millimeters or even 1 millimeter. That's tiny. That's much smaller than a grain of rice.
KELTO: This got cancer researchers pretty excited. Then in 2011, a study showed that spiral CT scans could reduce lung cancer deaths by 20 percent. That, Henschke says, translates into thousands of lives a year.
HENSCHKE: Because lung cancer is such a big killer in the U.S. and worldwide.
KELTO: But Dr. H. Gilbert Welch, a professor of medicine and health policy at Dartmouth, says there's a major drawback to these scans.
H. GILBERT WELCH: It's the two-edged sword. It can see very early cancers, but it could find small cancers that were never going to matter.
KELTO: Many cancers grow slowly and never really become dangerous, he says. And more often than not, the things that CT scans find aren't cancerous at all. In the study, 1 out of every 4 people had tests that came back positive for cancer when the person didn't have cancer. For some people, that led to risky follow-up tests like biopsies, where a needle is inserted into the lung.
WELCH: Sometimes that creates problems, like causing someone's lung to collapse.
KELTO: Now, Welch isn't saying that the lung study was bad science. A large panel of experts reviewed the data and determined that, overall, CT screening does more good than harm. They gave it a B rating on an ABCD scale. And because of that rating, Medicare and insurance companies now pay the full cost of the test for certain smokers. People age 55 to 77 who have smoked the equivalent of a pack a day for 30 years are eligible. That's millions of Americans. But Welch's concern is this; the radiologists in the study were highly skilled. The doctors were cautious and clearly explained the risks of the test. But in everyday medical settings, he says, that won't always be the case.
WELCH: The harmful effects of screening might actually be greater in practice.
KELTO: In other words, the net benefit of CT screening might not exist in the real world. Dr. Andy Lazris sees a lot of aging smokers. He's a primary care doctor in Columbia, Md. He's looked carefully at the data and is not enthusiastic about using CT scans to look for lung cancer.
ANDY LAZRIS: A lot of people are going to get these false alarms, and a lot of people are going to get excessive testing and potential harm.
KELTO: To help his patients understand the odds, he shows them a picture. It's a theater seating diagram.
LAZRIS: Out of these thousand seats of a theater, there are three and a half blackened seats, which is barely visible in the theater, and these are lung cancer deaths averted with spiral CT.
KELTO: Three out of every 1,000 people will survive lung cancer because of the test.
LAZRIS: Then if you turn the page and show another theater, you'll see lots of seats are black, and this is a crowded theater. So out of 1,000 people, 233 people will have persistent false-positives.
KELTO: False-positives that lead to more tests, which means more exposure to radiation and possible complications from things like biopsies. There can also be extra costs involved and stress. Lazris shows these theater diagrams to a lot of his patients, and he gets a wide range of responses.
LAZRIS: Some people, if there's one seat filled that says this is how many people benefit, they'll point to that and they say that's probably me. I'm not taking any chances. I'm getting this test. Other people will see five or six seats filled, they look at me and say, are you kidding? I'm that going for test like that. That's not worth it.
KELTO: But in either scenario, Lazris says, he's done his job because he's helped his patients understand the chances and then let them make the choice. Anders Kelto, NPR News, Washington.
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